Break the cake into fine crumbs and add the cream cheese. Combine until a dough forms.
Divide the dough into 6 equal size balls. Add a food colouring to each ball and mix until smooth. Flatten each ball between two parchment papers and place in the freezer for 30 minutes to an hour.
Using a small round cookie cutter, cut as many shapes as possible in each colored dough.
Stack a disk of each colour, creating a rainbow: red, orange, yellow, green, blue and purple. Slightly press down and freeze again for about 30 minutes.
Melt the white chocolate, add pink food colouring and mix well.
Dip a stick in the melted chocolate and insert through the disks. Let dry slightly then dip each rainbow cake in melted chocolate. Let dry on parchment paper for 30 minutes and enjoy!